Question

10 assertion and reason class 8 synthetic fibres and plastic ​

Answer 1

1. Rayon is obtained by the chemical treatment of ................

2. ............is the synthetic fibre used to make parachutes.

3. The synthetic fibre which resembles wool is ........

4. Polycot is a mixture of ............ and cotton.

5.The plastic which can be deformed easily on heating is known as.............

6. ................ is used to make handles of utensils.

7. A material which is not easily decomposed by natural processes are called ..............

8. Plastics are ................... of heat and electricity.

9. Uniforms of firemen have a coating of ................... to make them flame resistant.

10. ................ is used for non-stick coating on cookware.

ASSERTION-REASON QUESTIONS

Select the correct option for the following assertion-reason questions:

a. (A) is correct and (R) is the correct explanation of (A).

b. (A) is correct and (R) is not the correct explanation of (A).

c.(A) is correct and (R) is wrong.

d. (A) is wrong and (R) is correct.

1. Assertion(A): Bakelite is used for making electrical switches.

Reason(R): Bakelite is a poor conductor of electricity.

2. (A) Thermosetting plastics can not be remoulded.

(R) Thermosetting plastics can be softened on heating.

3. (A) Synthetic fibres are more popular than natural fibres.

(R) Synthetic fibres are more durable and less expensive.

4. (A) Nylon fibres can not be used for making ropes for climbers.

(R) Nylon fibres are very strong fibres.

5. (A) We should not use synthetic fabrics while working in the kitchen.

(R) Synthetic fabrics dry up quickly and are easy to wash.

SHORT ANSWER QUESTIONS:

1. Which fibre is called artificial fibres? Why?

2. List five uses of nylon.

3. What are the uses of PET polymer?

4. What are the characteristics of synthetic fibres?

5. Differentiate thermoplastics and thermosetting plastics.

Answer 2

Fibers are thread-like structures that are useful for the production of various products.

1. Assertion(A): Natural fibers are obtained from nature. Reason(R): Natural fibers are obtained from animal and plant sources.
2. (A): Synthetic fibers are man-made fibers. (R): They are used in manufacturing clothes.
3. (A): Synthetic fibers are also called man-made fibers. (R): They are created in laboratories.
4. (A):  Nylon and Polyester are synthetic fibers. (R): Cotton and wool are naturally occurring fibers.
5. (A): Silkworm feeds on mulberry leaves. (R): They produce natural fibers.
6. (A): Rayon is not completely a synthetic fiber. (R): The process of forming rayon has a touch of nature.
7. (A): Thermosetting plastics are cups, mugs, etc. (R): Thermosetting plastics can change their shape even after providing sufficient heat.
8. (A): Recycle, replace, reuse are the important 3R's. (R): There is another important 3R's.
9. (A): Governmental action the waste management. (R): Introduced the importance of R's.
10. (A): Pollution has been increasing for the last couple of years. (R): Most of the sea animals die due to consumption of them.